serial: 8250: 8250_omap: Fix unused variable warning

With commit 439c7183 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable"),
below warning is seen with W=1 and CONFIG_SERIAL_8250_DMA is disabled:

   drivers/tty/serial/8250/8250_omap.c:1199:42: warning: unused variable 'k3_soc_devices' [-Wunused-const-variable]

Fix this by moving the code using k3_soc_devices array to
omap_serial_fill_features_erratas() that handles other errata flags as
well.

Fixes: 439c7183 ("serial: 8250: 8250_omap: Disable RX interrupt after DMA enable")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Link: https://lore.kernel.org/r/20201111112653.2710-2-vigneshr@ti.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>